Surface treatment pad



FIG. 1 is a top, front, right side perspective view of the surface treatment pad;

FIG. 2 is a front elevational view thereof, the back, right side and left side elevational views being identical thereto;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a bottom plan view thereof.

The structure in broken lines forms no part of the claimed design. 

The ornamental design for a surface treatment pad, as shown and described. 